Erty's Laboratory

This is my more serious blog that will feature science and hobby projects.

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My first ever SSTC

Powered by a Mazilli ZVS driver at 12V and probably way out of tune from the resonant frequency of the secondary. Now just to try calculating that resonant frequency.

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This is the diagram of the current flyback driver circuit I'm using (not showing the fan for the MOSFET). Pin 6 of the LM386N is connected to the same side of C1 as the NE555 on the +12V rail.

The reason for adding C5 along with C4 is to handle more rapid changes in current which C4 otherwise would be too slow to react to. R5 was simply added to divide the audio signal voltage down to about 0.2Vpeak so I wouldn't need to adjust the standard 26dB gain of the LM386N. The switch at Pin 5 of the NE555 was added to give the option to choose between audio PWM, voltage PWM (by P3), or turn PWM off.

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I put a neon bulb in parallel with the primary of the flyback transformer in the previous circuit to indicate major voltage spikes going back into the circuit, and it has not lit up yet which indicates that any potential voltage spikes must be below about 100 volts.

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I measured the inductance of the Coil Cannon's coil to be 34mH, and the other coil gun (yet to be named) is at 22mH.

Their inductances are closer than I first thought. Hm…

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The old coil of the Coil Cannon pretty much kept its shape while and after it was removed.

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So I upgraded my old Coil Cannon (which fires 13mm steel marbles) with a much larger coil of a slightly thicker wire.

The outside of the coil has been covered with iron plates, however I just realized this won't help much considering much of the flux will still leak out from the sides.

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The hypothesis that the iron plates would boost the efficiency of the coil gun was confirmed. Sent the projectile flying several times faster than that of earlier designs, making it overshoot its intended target by a long way.

Now to try to find my projectile, and later try out a wider projectile which should work even better than the current one since it will fill more of the barrel and eliminate some of the magnetic flux leaking into the air gap.

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A new coil gun I made last night.

The coil has been surrounded by iron plates to hopefully help stopping the magnetic field leaking and instead trapping it inside the coil, which should boost its efficiency.

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I decided to try to power my SGTC with a ZVS-driven flyback transformer. I haven't tuned it yet and the tip of one of the spark gap electrodes broke so it's being a bit unstable, but it was enough to make an oven lightbulb glow up.

12V input voltage.

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So I just made my own ZVS driver and tested it on my homemade flyback transformer. It melted some of the wire and I accidentally flung a piece of molten copper onto the plastic sheet I kept the transformer on top of.

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Because of popular demand, here's a festive aluminium tree on top of my SGTC.

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More experimentation with corona discharge.

I think I'm ready to try out more complex shapes now.

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Normally when you work with high voltage, you try to suppress any corona discharge with insulators and by reducing potential gradients by using large, round, and smooth conductors. This is an example of what happens when you do the opposite; conducting high voltage through a complex shape with sharp edges made out of bare, thin aluminium foil.

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SGTC streamer in animated GIF format.